As egg-laying hens age the eggs which they lay, although becoming larger in size, exhibit a progressive decrease in eggshell thickness. Ultimately, the eggs are characterized by such thin shells that the loss due to breakage makes it uneconomical to maintain the hens for their egg production since the cost of the feed becomes greater than the number of marketable eggs produced. This pattern generally is found to occur after at least one year of egg production. Two procedures, appear to be available to address this problem, both of which are quite drastic: (1) the hens can be sacrificed and used as a food source; or (2) or the hens can be induced to molt. Molting can be induced either by starving the hens for a period of time or by withdrawing from their diet an essential nutrient which will bring about a loss in weight. Then, about eight weeks after molting, the hens are returned to egg-laying productivity. The eggs produced after molting tend to be smaller in size than before molting and have thicker shells. By this means the hens are returned to egg production on an economically sound basis for perhaps an additional year. As mentioned above, either of these treatments is considered rather drastic since hens subjected to such treatment must first recover their weight and health before they again are productive and a percentage of hens subjected to such treatment do not survive. Also, it is impractical to treat hens en masse by either of such procedures.